1839.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



417 



(juer the elenicnts, aiul set at defiance calius, contrary winds, and even tem- 

 pests tlicniselves. Passages will become ([uirkcr, the time of arrival of 

 packets may lie calculated like that of a land {lispatcli. No more shall we 

 await upon the shore for weeks, for months togethei', oiu- hearts torn liy 

 anxiety, to seek witli a distrustful eye in the limits of the horizon for the un- 

 certain outlines of the ship, which bears to you a father, mother, brother, or 

 a friend. The steam-engine in fine, dragging in its train thousands of travel- 

 lers, will run upon the iron road with greater speed than the swift horse 

 can'ying only the unweighted jockey. 



This is, gendenicn, h\it a very brief sketch of the benefits conferred upon 

 the world by the machine of wbicli Papin laid the germ in his works, and 

 which Watt carried to admirable perfection. Posterity certainly will not 

 weigh them in the balance with labours much more vaunted, and the real 

 influence of which, before the tribunal of reason, will always remain circum- 

 scribed to the circle of a few individuals, or a trifling lunnbcr of years. 



Formerly the age of Augustus was spoken of, the age of liOuis XIV., 

 eminent minds have already maintained that it would lie right to say the age 

 of Voltaire, Rousseau and Montesquieu. For my jiart, I do not hesitate to 

 assert that when to the inuuense services already rendered by the steam-en- 

 gine, shall be added all the wonders which it promises to \is still, grateful 

 nations will speak also of the ages of Papin and \Vatt. 



APPENDIX. 



A biography of Watt intended to make a part of our collection of memoirs 

 would be certainly incomplete if it did not contain a list of the academic 

 titles, which the illustrious engineer had received. Tliis list besides only re- 

 quires a few lines. 

 Watt was elected 



Fellow of the Royal Society of Edinburgh in 1784. 

 Fellow of the Royal Society of London in irS.*). 

 Mend)er of the Batavian Society in 17S7. 

 CoiTcsponding Member of the Fi'ench Institute in 1908. 

 In 1811 the Academy of Sciences of the Institute conferred on Walt the 

 highest honour in its power, that of nominating him one of itx pu/ht Foreign 

 Members. 



By a spontaneous and unanimous vote of the Senate of the University of 

 Glasgow, granted to Walt, iu 18015, the honorary degree of Doctor of Law. 



ON THE COMPOSITION OF WATER. 



An HisTonicwL Note, by the Right Hon. Lokd Brougham, F.R.S, 

 AND Member of the National Institute of Francf. 



There is no doubt that in England, at least, researches into the discovery 

 of the compositions of water have had for their origin the experiments of 

 Warltirc, related in the .'")th volume of Priestley.* Cavendish quotes them 

 expressly, as having suggested to him the idea of his labour.f The ex- 

 periments of Warltire consisted in the firing, by means of an electric 

 spark, and in closed vessels, a mixture of oxygen and hydrogen ; two 

 things, it was .said, resulted from it, 1st, a sensible loss of weight, and 

 2ndly, the precipitation of moisture on the sides of the vessels. 



Watt says by inadvertence in the note at ])age .SSS of his paperj, that the 

 aqueous precipitation \vas observed for the first time by Caveinlish, but 

 Cavendish himself declares p. 127, that Warltire had perceived tlie slight 

 watery deposits, and quotes on this subject the .5th volunu^ of Priestley. 

 Cavendish could not determine any loss of weight ; he observes that the 

 attempts of Priestley had led him to the same result^, and adds, that the 

 moisture deposited did not contain any impurity (literally u»// sooty matter). 



* WinUiie*s leUer, dMted from Birmingham, the ISIh of April, 1781, was publislu;il by 

 Dr. Priesrlcy in ilie 2ncl volume of liis Experiments and Ottsi^rvationsrclatint/ litvariMitt 

 brunettes of Aatural Philosophy, toith a contiuttation of tlte Obseycnliuns (in Air, 

 forming in fiict tlie 5lli volume of Experiments and Observations on different Itimls of 

 Air, priotfcl .it ninninylmm iu 1781.— f'TVo/e by Mr. Watt, Junior.) 



t Pliilosophical Trans'ictions, 1784, p. 1'16. 



1 Philosopliical Transactions, 1784. 



§ The note of Cavendisli at pai;e 1-27, appears to imply that Priestley had not pri- 

 ceived any loss of weight, but I do not find this assertion in any of the woiks of the 

 Birminghatu eliemist. 



The first experiments of Wailfire on the conflagration of the gases, were made in a 

 copper globe, the weigiit of which was 14 ounces, and the volume three pints. The 

 author wished " to determine whether heat was or was nol ponderable." 



Wailtire nt first describes the methods of mixing the g ts and ailjusting the scales, and 

 then says, " 1 always balanced exactly the vessel, full of ctmimon air, in i>r(ler that the 

 ditference of weight by tile iutroductiou of iullammalile air might allow me to judge 

 whether the mixture had been etfected in the wished for proportl(ms. Tlie passage of 

 the electric spark made the globe hot ; after it had cooled again by exposure to the air 

 of the room, I hung it np again on the balance; 1 always iouml a lo-s ol weiiiht, but 

 there were dilferences between one experiment and another. The me.in loss was two 

 grains-" 



Warltire eonlinues thus, " I have exploded my gases in glass vessels since! have seen 

 you fPriestley) do it htcly, and I tiave observeil as you Din, that although the vessel was 

 clean and dry before the explosion, it was afterwards covered with dew and a sooty 

 substance." 



On balancing the claims, does not the merit of having perceived Ihe dew seem to rest 

 with Priestley ? 



In some remarks which Priestley adds to his correspondent's letter, he confirms the 

 loss of weight, and adds, " 1 do not think, however, that the hold opinion that the latent 



After a great number of trials, Cavendish found out that if a light be put 

 to a mixture of common and inflammable air, composed of 10(10 parts of 

 the first and 4'2:3 of the second, " about a fifth of the common air, anil 

 almost all the inflammable air, lose their elasticity, -.mi form, hi/ condcnsntion. 

 the dew which covers the glass." On examining the dew. Cavendish 

 found that this dew was pure water, and he concludetl from it, that all the 

 inflammable air and about a sixth of the common air, returned into pure 

 water." 



Cavendish burned in the same mannei a mixture of inflammable air ;ind 

 dephlogisticated air (hydrogen and oxygen), The liquid precipitated was 

 always more or less acid, according as the gas burned with the iuttammablt! 

 air contained more or less phlogiston ; this acid so engendered was nitric 

 acid. 



Mr. Cavendish decided that " almost all the inflammable depblogisticatett 

 air (.5 turned into pure iimtcr," and further, that if those airs eouhl be ob- 

 tained in a complete state of jjiirity, all of it would be condensed." If 

 comiTion air and inflammable air do not give out acid when they are burned, 

 it is, according to this author, because tlien the beat is not intense enough. 



Cavendish declares that his experiments, with the exception of those re- 

 lating to acid, were made in the summer of ITi^I, and that Priestley was 

 acquainted with them ; he adds, " one of my friends gave soitie account to 

 Lavoisier, last spring (178,'J), as also of the conclusion which I had drawn 

 that dephlogisticated air is water deprived of phlogiston. But at that time, 

 Lavoisier was so far froin thinking such an opinion legitimate, that up to 

 the time that be made u[i his mind to try the experiments for himself, he 

 found some difliculty in believing that almost the whole of two airs could 

 be converted into w.ater." 



The friend mentioned in the preceding passage was Doctor, afterwards 

 Sir Charles Blagden. It is a remarkable circumstance that this passage of 

 Cavendish's work seems not to have made part of the original paper pre- 

 sented to the Royal Society ; the paper seems to have been written by the 

 hand of the author himself, but the paragraphs 134 and 1.35 were not in it 

 originally; they are added, with a mark of the place to whicli they belong ; 

 the writing also is not that of Cavendish, the additions .are in Blagden's 

 hand-wTiting. It was lie who must have given the details relative to La- 

 voisier, with whom it is not said that Cavendish kept up a direct corres, 

 pondence. 



The date on which Cavendish's paper was read is the 15th January, 1784. 

 The volume of the Philosophical Transactions of which this paper forms ,1 

 part, did not ajipear for six months after. 



The paper of Lavoisier (Volume of the Academy of Sciences for 1781), 

 had been read in November and December, 17s3. Several additions were 

 afterwards made to it ; it was published in 1784. This paper giv(.'S an ac- 

 count of experiments In the month of June, 1783, at which Lavoisier lui- 

 nouuces that Blagden was present ; Lavoisier adds, that this English phi- 

 loso])her had informed him " that already C,a\endish having burned 

 inflammable air in closed vessels, had obtahied a very sensible quantity of 

 water;" but he says nowhere that Blagden mentions the conclusions drawn 

 by Cavendish from these experiments. 



Lavoisier declares expressly that the weight of the water was equal to 

 that of the two gases consumed, unless, contrary to his own opinions, sen. 

 sible weight was attributed to the heat and light disengaged in the experi- 

 ment. 



This account is in discordance with that of Blagden, which according to 

 all ]irobability, was written as a refutation to that of Lavoisier, after the 

 paper of Cavendish was read, and when the volume of the Academy of 

 Sciences had not yet arrived in England. This volume came out in 1784, 

 and certainly it could not have arrived in London, neither when Cavendish 

 read his paper before the Royal Society, nor for still stronger reasons, when 

 he com]nled it. It must be besides reinarkcd, that in the passage in the 

 manuscript paper of Blagden, only one communication of experiments is 

 mentioned, a communication to Priestley. The experiments, it is there 

 said, were made in 1781, but the date of the communication is nowhere 

 mentioned, neitlier are we better informed whether the conclusions drawn 

 from these experiments, and which ;iccording to Blagden, were commnni- 

 eated by him to Lavoisier in the summer of 1783 were equally included in 

 the communication made to Piiestley. The Birmingham chemist in his 

 jiaper dravvn up before the month of April, 178.3, read in Jiuie of the same 

 j-ear, and .[uoted by Cavendish, says nothing of the theory of this latter, 

 although he quotes his experiments. 



Several propositions result from the foregoing : 



l.st. Cavendish in the paper read before the Royal Society on the 1.5th 

 January, 1784, describes the principal experiment of the inflammation of 

 oxygen and h)'drogeu in closed vessels, tind quotes the water as the product 

 of this coinbustiou. 



•2nd. In the same paper, Cavendish draws from his experiments the con., 

 elusion that the two gases mentioned transform themselves into water. 



3rd. In an addition of Blagden made with the consent of Cavendish, the 



reater scale. If tliat is confirmed, it will he a remarkable fact, and one which wil 



the greatest honour to VVarltire's sagacity. 



it of bodies is a sen-ible part of their weight, can be admitted without experiments oa 



■ It must be l.irthcr observed," continues Priestley, " that at Ihe lime that lie ( Warl- 



■) saw Ihe deiv on the insiilc of the closed vessel of glass, he said that it conlirmed an 



ni.m which he had long had— the opinion that eominon air gives np its humidity 



en it is phlo'jislicatetl." 



1 is Iherebue evident that Warltire explained the dew by the simple mechanical prc- 



iiation of the liygroinetrical water contained in eominon air.— ( Note of Mr, fVattf 



nior.J 



2 M a 



cq, 

 1 .Iu 



